'alpha-haemolytic' originates from Modern English, combining 'alpha' (from Greek 'alpha', the first letter of the Greek alphabet) and 'haemolytic' (from New Latin/Greek roots 'haemo-' meaning 'blood' and '-lytic' from Greek 'lytikos' meaning 'able to loosen or dissolve').

'haemolytic' comes from New Latin 'haemolyticus', formed from Greek 'haima' ('blood') + 'lytikos' ('able to loosen/dissolve'); this was adopted into scientific Latin/English, and combined with the Greek-derived 'alpha' to form 'alpha-haemolytic' in modern microbiological usage (with a parallel US spelling 'alpha-hemolytic').

Initially the components referred simply to 'alpha' (the letter/type) and 'haemolytic' ('causing blood breakdown'); over time the combined term came to denote specifically the distinctive partial (greenish) hemolysis pattern seen on blood agar and organisms that produce it.